Tank structure



' Nov. 6, 1923. 1,473,595

R. V. BINGAY TANK STRUCTURE Filed June 2. 1920 2 Sheets-Sheet l ll I l i V l Q l# i F f s l -k l Q Nov. 6, 1923. 1,473,595

R. V. BINGAY TANK STRUCTURE Filed June 2 1920 2 Sheets-Sheet 2 50 bottom M of tank K. The tank Patented Nov. 6, 1923.

UNI-TED STATES 1,413,595 PATENT OFFICE.

ROBERT V. BINGAY, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO PITTSBURGH TBANSFOBIEB COMPANY, A CORPORATION OF PENNSYLVANIA.

TANK STRUCTURE.

Application nled June 2,

To all whom it may concer/n.'

Be it known that I, ROBERT V. BINGAY, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented cerl tain new and. useful Improvements in Tank Structures, of which the following is a specification.

This invention relates to electrical transformers and i particularly to transformers cooled by the circulation of oil in a tank.

The chief object of the invention is to provide a transformer and tank construction that is inexpensive and strong and adapted to provide for the etlicient circulation of the cooling oil. A

The transformer tank is preferably formed of sheet steel and further objects of the invention particularly in the method of buildwi l appear from the following description taken 1n connection with the accompanying drawings in which: Fig. 1 is a vertical sectional elevation of a transformer illustrating a specific embodiment of the invention. p

Fig. 2 is a partial plan view of a side section of the transformer tank 1n the process of formation. f e

Figs. 5, 5 and 7 are edge views of said side section illustrating successive steps in the formation thereof.`

Fig. 5 is an edge view of a-moditcation. Figs. 4, 6 and 8 are perspective views corresponding to Figs. 3, 5 and 7 respectively. Fig.' 6al is a perspective view of a modlfication.l

Fig. 9 is a perspective view of a portion 40 of the tank from inside.

Fig. 1U is an end view of the tank sides.

Figs. 11 and 12 are vertical sectional views of details, and

' Fig. 13 is a vertical elevation of the tank in lace on its base.

the specific embodiment of the invention shown in Fig. 1, a transformer T for instance of the double etic circuit type, is supported in frame wor F restln on the stands" on the base B and has a cover C fastened to its top by clamps 20. Bolts() extending upward from the frame, F pass throu h the' cover C and have their ends enclosed y air up the tank from standard steel parts` 1920. serial n. sse,115.

tight caps 21. The cover C also carries the primary and secondary terminal insulators N and .NL and the frame F carries a superstructure S for supporting the leads L to the transformer coils and the terminals.

The tank K is preferably of sheet metal and preferably circular, oval or rounded in section and the sides 22 are corrugated to a depth dependent upon the size of the tank and the relative cooling surface required. Hitherto the depth of these' side corrugations has been limited b considerations of strengthand the ydiflicu ty and ex lnse of producing deep corrugations. Thes allower lecorrugatlons glve a correspondingly restricted cooling surface and often it has been necessary to resort tol extra cooling pi es' or l' circulating means where the availab e air coolin of the tank itself will be 'sufficient if proper y provided for. In the tank of thisY invention corrugations of the tank body may be of any desired depth and strength required by practice and at the same time these corrugations are formed from sheet metal plates in a simple and inexpensive manner and the resultantstructure is strong and 80 self-sustaining and when assembled with the top and bottom portions providesk a rigid,

durable container.

In building up the tank sides or body 22 a rectangular sheet 23 (Fig. 2) is chosen or cut from the standard sheet steel sizes in stock and the top and bottom edges of the sheet arenotched as at 24: leaving straight intervals 25 between the notches, and in the specific example shown leavlng half' intervals 25 at each end. The notched sheet 23 is then bent into a series of parallel corrugations (Figs. 3 and 4) and preferably the bends are made by a pivoted bender' 26 swinging around a former 27 and pressing 05 or Wrapping the sheet around the former. This method of bendin the corrugations in succession gives a pref etermined identical diameter to each bend and avoids any overstressing of the metalandany irregular or war d effects. vThe bends28, 29 at the ends of t e corrugations are separated by interlediate substantially flat portions 30 and ft .te inner bends 28 are made between `the notches24- while the outer bends129 are cen- 10B "HteIed' at the peaks 31 of the notches, the ends A of corrugated-sections having the form shown in Figs. 3 and 4., with theedges/of bends 28 at right angles to the sheet and the edges of bends 29 inclined. The corners 32 of the notches form a line near the inner bends 28.

The next ste in the formation of the tank 'body is il ustrated in Figs. 5 and G and comprises bending the corrugated section as awhole into a circular arc corresponding in diameter to the diameter of the tank being built. This is accomplished by pressing the inner bends 28 toward each other to slightly narrow the spaces between them and correspondingly spreading apart the outer bends to increase their spacing, a template being used to gage the spacing of the bends. When a number of sections have been formed and curved as shown in Figs. 5 and 6 these sections are assembled side by side in semicircular cradles 33 corresponding to the outer diameter of the tank and the assembled sections are welded together along their meeting edges which are on the inside of the tank, and in this way a circular section is built up in the form for instance of a semicircle and corresponding to half of the tank body. The other half of the tank body is similarly built up and the two halves are assembled together on circular heads or templates 35 (-Fig. 10) corresponding to the inner diameter of the tank andare bound thereon by outer hoops 36. The two sections are then welded together along their meeting edges at the inside of the tank.

The tank body soformed has its corrugations open at the top and bottom and the next step in the process is the closing of these corrugations in such manner as .to form a rigid arched structure in which the corrugations mutually support each other through solid connecting rings at each end of the tank. The closing of the ends of the corrugations is illustrated in Figs. 7 8 and 9 and comprises a flattening or turning over of the ends of the inner corrugations 28 as indicated 39. The end edges of these corrugations are thus fiattened out into substantially straight lines as indicated at 38 and the ends of the corrugations are spread so as to be brought toward and finally into contact with each other as indicated at 40 and 41. The edges ,of the intdrmediate portion 30 and the outer bends 29 are also ammered over and brought into contact along line 42 and welded securely together along this line. The hammering outward of the ends of the corrugations 28 forms the inclined flattened surfaces 39 and brings the extreme ends of these surfaces substantiall into the line of the corners 32 of the notches 24, forming a continuous annular ridge around the end of'ft'he tank lfrom which the corrugations incline in opposite directions.

This gives a strong archedI construction terminating in a solid continuous apex or peak; the end of each corrugation is arched.

with a central heavily welded seam, and all these arches of the corrugations converge to the top ring so that these corrugations are not only strong in themselves but reinforce and mutually sustain each other through their common connection. All vertical sections through this structure show a characteristic arched form and all horizontal sections also show continuous corrugations with arched connecting bends. With a tank constructed according to the method of this invention it is possible to use a very light gage of sheet steel and all sizes of tanks may be made from Stock onl about one sixteenth of an inch thick. It 1S only necessary to carry a very few sizes of steel sheets in stock and from these sizes the desired sections may be readily cut, the number of sections in the tank being easily varied so that a given size of sheet will serve for various sizes of tanks. Each sheet is easily notched to desired contour according to the job in hand and may benotched in part and left plain in part to provide any desired shape for the tank and the sheets before corrugating may be punched out with holes of a shape which will be circular in the finally bent form. The forming of the co1'- rugation bends around a mandrel bends the metal and does not draw or warp or weaken it or leave it with internal stresses. The final closing of the corrugations and welding is done with the tank sections bound together and braced against warping by the inner heads 35 and the outer bands 36.

The two ends of the -tank body are sub stantially identicaly and comprise a corrugated cylinder with the corrugations inclined and arched at each end and rigidly welded to a continuous annular end portion at each end. This tank body is very strong, irrespective of its connection with the bottom and cover pieces. At each end it rovides an annular beveled surface forme by the ring of inclined flattened surfaces 39 and this beveled s'urface serves for the attachment of the bottom and top pieces in a simple and very rigid manner. When the bottom and top pieces are in place, as hereinafter described, this strong tubular portion reinforces the end portions in such manner that each part is trussed against the other to receive the strains put upon the tank.

The bottom M of the tank is formed b a circular plate, preferably of rolled stee, with its edge flanged upwardl at an ang'le (Figs. V1 and 11) and this e ge flan e 45 of the bottom M is nearly at right ang es to the beveled surfaces/39 and is just fitted to an intermediate portion of these surfaces. 'With the bottom piece M assembled and clamped in place a heavy weld 46 is made in the corner between the surfaces 39 and the liange so that the bottom surface of the tank is below the surface of this weld which will therefore be held spaced from the base B of the transformer in finally assembled osition. This Hanging-of the bottom plate 'gives this plate an arched construction and protects it against warping due to the heat of the welding operation and due to any strains on it in service, and this arching at the bottom also holds the welded seam away from contact with the base or other surfaces so that'this seam does not collect moisture andl become rusty or weaken or wear in use. This construction permits the bottom plate and the top ring, or either, to be made either thicker or thinner than the metal in the tank body, or of the same thickness as may be most advantageous.

The top of the tank body has welded to it the steel or iron angle ring 50, formed by rolling an angle into circular form with its flan 51 inclined at substantially the angle oethe tank cover C and the ends of the circle welded together. This ring 5.0 is sized to fit into the top of the tank and en gage an intermediate portion of the beveledg surfaces 39 at the top and is fastened in place by heavy welding 52 all around in the annular corner between the surfaces 39 and ring 50. This ring forms additional reinforcement of the tank body and provides a strorg and simple connection for the'y tank 4cover The cover C which may be of about the same thickness of sheet steel as the -bottom M is crowned as' shown and fastened to the ring bv clamps 20. This coverlfispro-- vided wit the central flanged opening 55 and with terminal insulators N and N2 for the leads. The bolts O of the frame F pass through this cover and are adapted to have eyes screwed on to their up r ends for lifting the frame F and translcrmer T out of the tank, the cover being lifted with the transformer and the clamps 20 ha been released. Underneath.l the cover'C the bolts O carry nutsU bearing against the under surface of the cover and adjusted on the bolts topress upwardon the cover and downward on the frame F standing'on the bottom M of the tank. The weight of the transformer parts therefore is not carried by the tank sides but is transmitted directly to the` bottom M 'resting on base B. Projections 63 are welded to the edges of the tank cover the base B. For further strengthening, if

desired, `especially in the case of large tanks, one or more reinforcing bands may surround the tank and be welded to th`e outside bends ofthe corrugations. In this combiation the tank sides or body 22 instead of being under compressive stresses, except by the side bolts 64 at the edges of the cover as a casin .mit the use of sheet steel stock and this body is furthermore not required to sustain the weight of the transformer parts. The cor-1 rugations of the tankl body may be made of any depth to give the cooling surface required. These corrugations overhang at the sides and are formed with well rounded bends 29 to give a large passage for the circulation of the oil along the most exposedv surfaces and in their entire area provide an extended cross section acting like lar pipes for the circulation of the oil. This ystem in effect makes the! pipes or conduits 'of the corrugations have a great proportion of their surface exposedvto the air. An inner baille cylinder 60 or guide vane, may be provided just within the bends 29,

lto separate the inner' heated currents of oil from the outer cooled currents. The columnsof cooled o il in the corrugations are relatively heavy and pass down, rapidly through the corrugations drawing in heated currents'ofoil at the top 61 and at the bottom 62 replacin the'oil rising through the transformer cois.

By the method of this invention the rela-4 tive area of the outer cooling flutes and the lnner passages through and around the coils and core may be made in most effective proportion and this` circulatory system pro-y vides definite areas of heating and cooling, avoids interference between the yrising and forced circulation which by the outer rapid passingof the oil down through the corrugations distributes the heated oil over a larger 'area of the transformer sides and instead of accumlulating as heretofore within a reatively small area at the top with slow and sluggish progress down the sides is rapidly circulated downward through the pipes formed by the corrugations. The temperature gradient at the sides therefore is much less'abrupt and the cooling taking place over a much larger area is much more eilicient.v

The tank of this invention also provides unobstructed paths for the cooling air rising and through. these holding bolts 64 pass to descending currents, and in effect gives a around the sides and in between the corru- 'i over a large proportion of their lengthLof path;` All of these .conditionsrmake .for 'a thorough and efficient transfer of heat from the oil within the -tank to the air outside so i bility in service.

that the tank of this invention will efficiently cool a transformer under conditions where it has heretofore been necessary to use extra tions. The number of sections 23 in agiven transformer body is a matterA of the most `economical use of the stock in handy after the desired depth of the corrugations and the "total areaof the body is determined. With transformers 4of excessively large size or where reat strength is .required an increase in t e gage of metal in the body may make it economical to make only a single corru ation in eachl section 23. c In such case t e bend of this corrugation is directed outward andthe inner meeting edges of adjacent sections are also flanged over and turned outward and Welded together along the inside between theser flanges as indicated at 66` (Figs. 5"L and 6).

While this invention has been illustrated in connection with a specific embodiment of transformer and tank it is not confined thereto but is intended to cover such modifications thereof as fall 'within the scope of the appended claims. It will also be understood that the parts may, ifl desired, be

fbrazed instead of welded.

I claimzv l. A tank comprising a body portion of corrugated sheet metal having corrugations with outer bends formed without Welding and the opposite edges of the ends of the corrugations being respectively rounded over and welded together to form an arch,

y the bodies of the corrugations extending between `rsaid welds being bent to form a con-- tinuousfinclined surface meeting said welds in a continuous ridge, the whole forming a self sustaining unitary structure.

2. A transformer tank comprising a body portion.' of corrugated sheet metal having corrugations with outer bends formed without welding and the ends of the corrugaltions respectively rounded over and welded together to form a rounded arch, the bodies :of the corrugations extending between said :welds being bent to form a continuous inclined surface meetingV said welds in a contin'upus'ridge, the whole forming a self sustaining unitairy structure., `and 'a bottom plate welded to the inclined surface adjacent the ridge.

3. A transformer tank having'a body por'-4 tion of corrugated sheet metal comprising a series of sections notched and corrugated so that the notched ends of the corrugations are inclined and having the inclined edges of the notched portions welded together, the inner ends of the corrugations being flattened to form an inclined surface meeting the welds in the form of a ridge.

4. A transformer tank having a body portion of corrugated sheet metal comprising a series of sections notched and corrugated so that the ends of the corrugations are inclined and having the inclined edges welded together, the inner ends of the corrugations being flattened to form an inclined surface meeting the welds in the form of a ridge, and a bottom plate having its edges welded to the inclined inner portion of the body adjacent the ridge.

5. A transformer tank having a body portion of corrugated sheet metal comprising a series of sections notched and corrugated so that) the ends of the corrugations are inclined and having the inclined edges welded together, the inner ends of the corrugations being flattened to form an inner oppositely inclined surface meeting the welds in the form of a ridge, a bottom plate having its edges welded to the inner portion of the body adjacent the ridge, Vand a cover supporting ring welded to the inner inclined i port-ion of the upper end of the body adjacent the ridge.

6. A transformer tank comprising a body portion of corrugated sheet metal with corrugations having outer bends formed without Welding and thel ends of the corrugations bent over to form a' flattened inclined surface on one side and a series of oppo- .sitely-inclined meeting edges on the other,

the'inclined surfaces and edges meeting in a I ridge, and welds formed along said meeting tank comprising a body portion of corrugated sheet metal, the outer bends of the corrugations being formed without welding and the opposite side edges of the ends of the several corrugations being rounded over to meet each other, the said opposite edges being welded together by a weld on the outer side thereof to form anl arch shaped end closure .for the corrugation.

8. AA transformer'tank comprising a body portion of sheet metaljnotched and corrugated so that the edges of the notches constitute the ends of the corrugations and are inclined inwardly and toward the body ends, respectively,l said inclined ends being ifounded over and welded together4 in arched orm.

9. A tank comprising a body portion of sheet metal, a rolled steel end portion having an upwardly inclined circumferential flange, the edge ofl which abutsbut does not lap the body portion, and s weld Vformed along the line of contact in the space between the body portion and the lower inclined surface of the flange.

10. A tank comprising a body portion of corrugated sheet steel having a lat circumferential surface and a rolled steel bottom portion, having an upwardly inclined circumferential flange, the edge of which abuts but does not lap the flat portion of the body portion along a circumferential line above the lower surface of said bottom, and a weld formedalong the said line of contact.

11. A transformer tank comprising abody portion of corrugated sheet metal with the upper ends of the inner corrugationswflab,

tened to form a surface inclined upwardly and outwardly from the axis of the tank, and a top ring formed by an angle rolled into circular form and welded at its meeting ends, the vertical side of the angle being welded to said inclined surface of the body portion and the horizontal side of the angle forming a cover supporting flange.

12. A transformer'tank comprising a body of corrugated vsheet steel having the ends. of the inner corrugations flattened to form an inclined surface, a bottom plate with its edge flanged upwardly and engaging against said inclined surface, and a weld formed in the groove between the lower surface 'of sfaid plate and the surrounding inclined surace.

13. A transformer tank having a body portion of corrugated sheet metal comprising a series of sections notched and corrugated so that the ends of the corrugations are inclined and having the inclined edges welded together, the inner ends of the corrugations being flattened to form an inclined surface meeting the welds in the form of a ridge, and an upwardly flanged bottom plate having the edges of the flange welded to the inner portion of the body adjacent the ridge. n

14. A transformer tank comprising a body portion of sheet metal having corrugations, the ends of which are shapedV to form inner circumferential inclined surfaces, a bottom comprising a metal sheet with upturned edges meeting said lower inclined surfaces and welded thereto, and a top portion welded to the upper inclined surfaces.

ROBERT V. BINGAY. 

